Scratch

matthew8092001 · 2012-05-26 16:46:34

Code:

package Stuff;
import java.util.*;

public class Derivative {

  
    public static void main(String[] args) {
        Scanner yay = new Scanner (System.in);
        System.out.println("Enter the ax^b function.");
        String get = yay.nextLine();
        int a = get.charAt(1).toInt;
        int b = get.charAt(4).toInt;
        System.out.println("The derivative is: "+a*b+"x^"+(b-1));
    }
}

It says: "char cannot be dereferenced." Any ideas?

Last edited by matthew8092001 (2012-05-27 11:23:19)

Harakou · 2012-05-26 18:15:16

Sounds like you've got a case where the index of the String you're referencing doesn't exist. Make sure that the string you enter is long enough (at least 5 characters long in this case.) If that's not it, could you describe the problem any further?

poopo · 2012-05-26 18:35:09

Code:

package Stuff;
import java.util.*;

public class Derivative {

  
    public static void main(String[] args) {
        Scanner yay = new Scanner (System.in);
        System.out.println("Enter the ax^b function.");
        String get = yay.nextLine();
        int a = get.charAt(0).toInt;
        int b = get.charAt(3).toInt;
        System.out.println("The derivative is: "+a*b+"x^"+(b-1));
    }
}

that should work. wink remember it starts with 0 not 1.

matthew8092001 · 2012-05-27 11:29:29

poopo wrote:

Code:

package Stuff;
import java.util.*;

public class Derivative {

  
    public static void main(String[] args) {
        Scanner yay = new Scanner (System.in);
        System.out.println("Enter the ax^b function.");
        String get = yay.nextLine();
        int a = get.charAt(0).toInt;
        int b = get.charAt(3).toInt;
        System.out.println("The derivative is: "+a*b+"x^"+(b-1));
    }
}

that should work. wink remember it starts with 0 not 1.

I just realized that and fixed that, but it still isn't working sad
@Harakou
Like I said, it says "char cannot be dereferenced."
I seriously have no idea what's wrong.

scratchisthebest · 2012-05-30 15:36:03

What line number?
Did you try adding () after toInt?
I'm not too familiar with Scanner, so these are just guesses, but toInt looks like a function to me.

Scratch

archived forums

#1 2012-05-26 16:46:34

[Java] Simple derivative calculator help?

Code:

#2 2012-05-26 18:15:16

Re: [Java] Simple derivative calculator help?

#3 2012-05-26 18:35:09

Re: [Java] Simple derivative calculator help?

Code:

#4 2012-05-27 11:29:29

Re: [Java] Simple derivative calculator help?

poopo wrote:

Code:

#5 2012-05-30 15:36:03

Re: [Java] Simple derivative calculator help?

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